Electrolytic marking apparatus including stencil holder



Dec. 6, 1966 B. w. MAYER 3,290,236

ELECTROLYTIC MARKING APPARATUS INCLUDING STENCIL HOLDER Filed Feb. '7,1963 INVENTOR.

BRUCE W. MAYER ATTORNEYS United States Patent My invention relates toelectrolytic marking apparatus and particularly to the stencil holderand the stencil utilized with such apparatus. i

An object of my invention is. to provide an improved stencil holderadapted to reciprocate 'with the reciprocating member of automaticelectrolytic marking apparatus. Another object is the provision of astencil holder adapted to hold a stencil in marking positionintermediate the marking head and a workpiece that is to be marked.

Another object is the provision of a stencil holder adapted for readyinsertion and removal of stencils in the replacement of stencils in theapparatus.

Another object is the provisionof a stencil holder particularlyadapted/to accommodate to the reciprocating motion of a marking head inautomatic or recurrently operated electrolytic marking apparatus.

Another object is the provision for an improved stencil particularlyadapted for accommodation in my improved stencil holder.

Another object is the provision for a cooperatively reacting stencilholder and stencil constructed for use with the reciprocating headofelectrolytic marking apparatus.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawing, in which:

.FIGURE 1 is an elevational view of my improved stencil holder andstencil showing the head of the marker and associated parts in lowerposition;

FIGURE 2 is .a view like that of FIGURE 1 except that it shows the headand associated parts in raised position;

FIGURE 3 is a view similar to FIGURE 2 by looking in the direction ofthe arrows 3-3 of FIGURE 2; and

FIGURE 4 is an enlarged perspective view of my improved stencil utilizedWith my stencil holder.

In views of the drawing; there isshown areciprocating member 11 which isan'elongated hollow member carried by a ram or arm of the apparatus, soas to recurrently raise and lower the: member 11. Included within thereciprocating member 11, but not shown, is a coil spring which urges anelectrode holder carried by the holder 11 downwardly. An-electrodeholder 12 iselectrically connected through member 11 with a flexibleelectrical wire 17 connected to a source of electrical energy.

A conductor rod or electrode 13 is secured to the holder 12 by means ofa screw 14, the rod 13 extending downwardly from the holder 12a-s shown.A. pin 16 extends laterally from'the holder 12 and out through .a slot15 in the wall of the reciprocating member 11. The innerengagement ofthe slot'1'5 and pin 16.is such that a limited relative movement ispermitted between the holder 12 and the-member 11. The spring, notshown, within the member 11 resiliently urges the holder 12 downwardlyand hence the pin 16 toward the lower end of the slot 15.

The upper end of the slot 15 limits upward movement of the holder 12 andpin 16 relative to the member 11.

Mounted upon the metal conductor rod 13 so as to reciprocate therewithis a cylinder or reservoir 18 adapted to hold or accommodate a supply ofelectrolytic solution utilized in the electrolytic marking operation.This cylindrical reservoir 18 has a cap 18B closing the upper end of3,290,236 Patented Dec. 6, 1966 the cylinder and accommodating the rod13 which extends through the cap 18B and axially through the reservoir18. The cylinder or reservoir also has a longitudinally extending rib18A disposed along its length. The rib 18A provides a non-circularcross-sectional shape to the outside contour of the cylinder 18.

Secured to and carried by the lower end of the electrical conductor bar'13 is a porous carbon head or electrode member 19. Member 19 closes thelower end of the cylinder 18 and is sufficientlyporous to permitelectrolytic solution within the cylinder 18 to seep through the head19. The head 19 is adapted to conduct electric current introducedthereto fromthe wire 17, holder 12 and conducto'r rod13. As seen in thedrawing, the carbon head 19 is shaped-to have a reduced end portion andopposite shoulders as illustrated. An absorbent pad 20 is disposed overthe reduced end of the head and held thereto by adhesive, bands or othersuitable means. The pad 20 receives and holds electrolytic solutionsupplied thereto through the carbon head 19. The electrolytic solutionin the pad 20 receives an electric charge from the head 19.

Slidably mounted on the cylindrical reservoir 18 is a stencil holdercomprised of a cross-piece or saddle member 21 and dependent spaced sideportions 22A and 22B extending downwardly therefrom. The cross-piece 21has a hole extending therethrough which complements and accommodates thenon-circular cross section of the cylinder 18 having its rib 18Aextending therealong. Thus the cross-piece 21 may slide up and downrelative to the reservoir 18 but cannot rotate around the axis of thereservoir 18. The hole in the cross-piece is such, however, that it issmaller in dimension than the head 19 so that the cross-piece 21 in itslowermost position rests upon and engages the top of the carbon head 19,as better seen in FIGURE 3.

The two spaced dependent side portions 22A and 22B are disposedsubstantially parallel to each other and accommodate therebetween thehead 19 and pad 20. Disposed in opposite facing walls of the side pieces22A and 22B are grooves 220 and 22D, respectively. These grooves are forthe purpose of holding a stencil, such as the stencil generallyindicated by the reference character 23, in operating position below thepad 20.

The stencil 23 is a rectangular piece of stencil paper, fabric or othermaterial appropriately treated to operate and function as a stencil. Ithas formed therein the indicia of the mark to be impressed on thearticle or workpiece being marked. The making or preparation of thestencil and of the indicia perforation or their areas, are known and itis not necessary to here repeat. The main body of the stencil isof thefilm or sheet which is relatively flexible, that is, it will flexlaterally when pressed or forcibly engaged on one side.

Extending along'the main film portion 24 of the stencil 23 alongopposite edges thereof are reinforced and relatively rigid edge portions25 and 26, respectively. Preferably these edge portions 25 and 26 areformed by folded over additional paper or other material adhering to theedge portions so as to give additional thickness to the stencilalong itsopposite edge portions and to provide relative rigidity or stiffness tothe edge portion. The edge portions may also be thickened or made morerigid by adding hardenable plastic material along the edges or byfolding over the opposite edges to provide additional thickness and bycoating such folded edges with hardenable flexible material to producethickened and relatively rigid edge portions.

The stencil 23 is mounted to the holder by longitudinally sliding theedge portions 25 and 26 endwise into the respective grooves 22C and 22Dso as to position the relatively flexible film portion 24 below the pad20. It is seen in the drawing the grooves 22C and 22D are disposed toincline to a common plane through the opposite grooves 22C and 22D. Thegrooves 220 and 22D extend upwardly and inwardly toward the axis of thehead. Also the reinforced edge portions 25 and 26 are correspondinglyinclined at such angles so as to readily fit within the grooves onsliding the stencil endwise into the grooves of the holder. The holderhas a stop portion 22E at the rear end of the grooves 22C and 22D whichlimits the inward movement of the stencil 23 and thus assures the properalignment of the indicia of the stencil film portion 24 with the articleof the workpiece to be marked.

Supported on a suitable supporting base, such as a table top 29, is acarbon base electrode 27 which has a top surface upon which may beplaced an article or workpiece 36 to be electrically marked. An electricwire or conductor 28 connected to a source of electrical energy isconducted to the carbon electrode 27 so as to conduct electric energythereto. The wires 17 and 28 are of opposite polarity and so connectedwith a source of electrical energy that electrical energy of onepolarity is conducted to the workpiece 30 and electrical energy ofanother polarity is conducted to the pad 20 whereby electrical energyflows through the stencil 23 to electrically etch the workpiece 30 bythe electrolytic action of electrical energy in association with theelectrolytic solution in the pad 20 and apply to the workpiece throughthe perforations or like solution-conducting area of the indicia in thestencil.

In the operation of the apparatus, a stencil bearing the appropriatestencilled indicia thereon is mounted to the holder as described so asto position the film portion 24 below pad 20. The member 11 ispositioned upwardly as shown in FIGURE 2 and a workpiece 30 to be markedis placed upon the base electrode 27. The workpiece 30 is a metal objectupon which a marking is to be made by an electrolytic etching operation.The electrolytic solution in the reservoir 18 saturates the pad 20 andelectrical energy is supplied through wires 17 and 28 to provide therequired electric potential. The apparatus is then operated so as tolower the reciprocating member 11 from the position shown in FIGURE 2 tothat shown in FIGURE 1. This causes the head 19 and pad 20 to pressdownwardly and to cause the stencil 23 to be pressed by the pad 20against the workpiece 30. At this time the electrical energy is appliedso as to cause an electrolytic etching action to occur through thecooperation of the solution and electrical energy operating through thestencil. As the stencil 23 meets the resistance of the workpiece 30, theholder is raised to cause the cross-piece 21 or saddle to slide upwardlyalong the cylinder 18 from the position shown in FIGURE 2 to theposition shown in FIGURE 1. To assure a firm pressure of the stencilagainst the workpiece, the pad 20 and head 19 are resiliently urgeddownwardly against the workpiece 30 by the coil spring within thereciprocating member 11 which urges the holder, rod 13, and partscarried thereby downwardly toward the workpiece 30. Relative movementbetween the holder 12 and member 11 is permitted by the pin 16 withinthe slot 15. As is apparent, pressure against the film portion 24- andthe workpiece 30 and by the pad 20 which would otherwise tend todislodge or disengage the opposite edge portions of the stencil from thegrooves of the holder, is resisted by the angular inclination of theedge portions within the grooves. Thus the edge portions are so heldthat axially directed movement against the side of the stencil does notdislodge the stencil from the grooves in the holder.

It is thus seen by my improved holder and stencil, the stencil is alwaysheld in proper operative position, is not torn or dislodged, and isalways in proper alignment for the marking operation. There is no sideslippage nor other improper movement of the stencil along the surface ofthe workpiece. It has been found that rapid and autounderstood that thepresent disclosure of the preferred form has been made only by way ofexample and that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and scope of the invention as hereinafterclaimed.

What is claimed is:

1. An electrolytic marking tool combination including a holding devicefor holding a stencil in position relative to a reciprocal electrolyticmarking head to engage a workpiece to be marked upon movement of thehead downwardly to marking position adjacent the workpiece, comprisingin combination a crosspiece carried by said marking head, said stencilhaving a body of relatively flexible material displaceable from theplane common to the opposite edge portion thereof upon the said markinghead moving against the body of the stencil toward the workpiece, saidcr-ossqpiece having an open space extending therethrough foraccommodating said marking head and guiding reciprocal movement thereofrelative to the crosspiece, spaced dependent pieces carried by saidcrosspiece and extending downwardly therefrom to accommodate the lowerend of said head between said dependent pieces, said dependent pieceshaving oppositely disposed grooves, respectively, for accommodatingopposite edge portions of a said stencil extending between saiddependent pieces, said grooves being non-circular in cross-section andcomplementing the shape of non-circular edge portions of the stencil tolimit rotation of the edge portions in the respective grooves upondisplacement of the body of the stencil by the marking head movingtoward the workpiece, said grooves being inclined upwardly and inwardlytoward each other to hold said edge portions of the stencil angul-arlyto a horizontal plane extending between the openings of the said grooveswhereby said stencil is restrained against withdrawal from said groovesby downwardly exerted force on the stencil intermediate of said groovesby said head moving toward said workpiece, said grooves being open atone end of said dependent pieces, respectively, to permit the stencil tobe moved in and out of position between the dependent pieces by slidingthe edge portions, respectively, longitudinally of said grooves, saidgrooves being closed. at the opposite end of said dependent pieces,respectively, to limit the movement of said edge portions in saidgrooves and to fix the position of the stencil between said dependentpieces, said holding device being movable upwardly relativeto the saidhead upon said stencil meeting the resistance of a said workpiece in thedownward movement of said head toward the workpiece.

2. An electrolytic marking tool combination includmg a holding devicefor holding a stencil of a marking tool reciprocal to and from aworkpiece to be marked, said tool having a head and a pad carriedthereby, said pad being adapted to hold electrolytic solutionelectrically energized for etching of the workpiece through saidstencil, said stencil having relatively stiff opposite edge portions ofnon-circular cross-sectional shape and being relatively flexibletherebetween and subject to displacement from a plane through said edgeportions upon said head being moved thereagainst toward a saidworkpiece, said holding device comprising a saddle member having a baseportion adapted to be carried by said tool to be moved with the headtoward and away from a said workpiece, said saddle member having spacedside portions carried by said base portion to move therewith, said sideportions being adapted to be disposed on op- PQEilQ sides of said. headand pad, said side portions having spaced grooves adapted to beaccommodate opposite edge portions of said stencil to hold the stencilextended between the said side portions and in juxtaposition to saidpad, said grooves being non-circular in cross-section tocomplem'entarily interfit with said opposite edge portions of saidstencil to hold the respective edge portions against rotation therein,said grooves being disposed to hold said edge portions, respectively, inplanes offset from a common plane through the opposed openings of saidgrooves, respectively, to retain the said edge portions in said groovesagainst Withdrawal through the said openings upon application of forceon said stencil by said head moving toward a said workpiece, saidgrooves being open at one end to permit said edge portions to be slidendwise into said grooves, respectively, and being closed at theopposite end to limit movement of the said edge portions inwardly of thegrooves, said h-olding device holding a stencil having its opposite edgeportions in said grooves in juxtaposition to said head to'be placed inengagement with a said workpiece for the etching thereof upon movementof the head to the workpiece.

3. An electrolytic marking tool combination including a holding deviceas defined in claim 2 and including lost motion between the saddlemember and tool to permit the said head to proceed toward the workpieceafter movement of the holding device toward the work-piece is resistedby engagement of the workpiece with the stencil carried by the holdingdevice.

4. The combination of a holding device adapted to be carried by areciprocal electrolytic marking tool and a stencil carried by theholding device to be movable therewith to position the stencil injuxtaposition to the solu tion-carrying pad of the head of the tool andto position the stencil in etching location a-dajacent the workpieceupon movement of the tool to the workpiece, said stencil having opposedinclinable edge portions and said holding device having opposed inclinedgrooves for accommodating said edge portions, respectively, to disposethe said stencil intermediate said pad and a said workpiece to whichsaid tool is moved, said edge portions and grooves being non-circular incross-section and interfitting to resist rotation of an edge portion ina groove upon lateral pressure on the stencil, said edge portions andgrooves being co-mplementarily offset from a common plane through thesaid grooves to resist withdrawal of the ed e 4 portions lateral-1y fromthe grooves upon axial movement of the stencil intermediate of the edgeportions relative to said grooves, said grooves being open atcorresponding ends to facilitate sliding insertion of the respectiveedge portions therein.

5. An electrolytic marking device including in combination a reciprocalelectrolytic marking tool movable toward and away from a workpiece to bemarked, a tool having an electrolytic-solution carrying head, and astencil holder carried by said t-ool and having spaced side portionsdisposed on opposite sides of said head, said side portions havingparallel stencil-engaging portions adapted to engage and hold oppositeparallel edge portions of a stencil extending therebetween intermediatesaid head and a workpiece to be marked, said stencil-engaging portionsof the stencil holder each having opposite parallel walls adapted toengage opposite sides of a respective edge portion, said walls beingangula-rly inclined from a common plane through both thestencil-engaging portions to hold the stencil edge portions againstdisengagement from each stencil-engaging portion in direction toward theother stencil-engaging portion, said stencil-engaging portions 'beingopen at corresponding ends to rea-dily permit the stencil edge portionsof a stencil to be moved endwise into place in the stencil-engagingportions.

6.. A stencil holder as defined in claim 5 and in which stop means areincluded therein to limit the endwise movement of the stencil edgeportions in the said stencilengaging portions.

References Cited by the Examiner UNITED STATES PATENTS 958,991 5/1910Burton 220-41 X 1,451,816 4/1923 Evans 101l27.1 2,495,439 2/1950 Bumber220-41 X 2,498,129 2/1950 Lindsay 204-224 2,911,906 11/1959 Kiang101-125 2,967,813 1/1961 Lindsay 204-224 3,152,541 10/1964 Carlsen101-125 3,227,073 1/1966 Reich 101-125 FOREIGN PATENTS 399,950 10/ 1933Great Britain.

JOHN H. MACK, Primary Examiner.

A. B. CURTIS, W. VAN SISE, Assistant Examiners.

1. AN ELECTROLYTIC MARKING TOOL COMBINATION INCLUDING A HOLDING DEVICEFOR HOLDING A STENCIL IN POSITION RELATIVE TO A RECIPROCAL ELECTROLYTICMARKING HEAD TO ENGAGE A WORKPIECE TO BE MARKED UPON MOVEMENT OF THEHEAD DOWNWARDLY TO MARKING POSITION ADJACENT THE WORKPIECE, COMPRISINGIN COMBINATION A CROSSPIECE CARRIED BY SAID MARKING HEAD, SAID STENCILHAVING A BODY OF RELATIVELY FLEXIBLE MATERIAL DISPLACEABLE FROM THEPLANE COMMON TO THE OPPOSITE EDGE PORTION THEREOF UPON THE SAID MARKINGHEAD MOVING AGAINST THE BODY OF THE STENCIL TOWARD THE WORKPIECE, SAIDCROSS-PIECE HAVING AN OPEN SPACE EXTENDING THERETHROUGH FORACCOMMODATING SAID MARKING HEAD AND GUIDING RECIPROCAL MOVEMENT THEREOFRELATIVE TO THE CROSSPIECE, SPACED DEPENDENT PIECES CARRIED BY SAIDCROSSPIECE AND EXTENDING DOWNWARDLY THEREFROM TO ACCOMMODATE THE LOWEREND OF SAID HEAD BETWEEN SAID DEPENDENT PIECES, SAID DEPENDENT PIECESHAVING OPPOSITELY DISPOSED GROOVES, RESPECTIVELY, FOR ACCOMMODATINGOPPOSITE EDGE PORTIONS OF A SAID STENCIL EXTENDING BETWEEN SAIDDEPENDENT PIECES , SAID GROOVES BEING NON-CIRCULAR IN CROSS-SECTION ANDCOMPLEMENTING THE SHAPE OF NON-CIRCULAR EDGE PORTIONS OF THE STENCIL TOLIMIT ROTATION OF THE EDGE PORTIONS IN THE RESPECTIVE GROOVES UPONDISPLACEMENT OF THE BODY OF THE STENCIL BY THE MARKING HEAD MOVINGTOWARD THE WORKPIECE, SAID GROOVES BEING INCLINED UPWARDLY AND INWARDLYTOWARD EACH OTHER TO HOLD SAID EDGE PORTIONS OF THE STENCIL ANGULARLY TOA HORIZONTAL PLANE EXTENDING BETWEEN THE OPENINGS OF THE SAID GROOVESWHEREBY SAID STENCIL IS RESTRAINED AGAINST WITHDRAWAL FROM SAID GROOVESBY DOWNWARDLY EXERTED FORCE ON THE STENCIL INERMEDIATE OF SAID GROOVESBY SAID HEAD MOVING TOWARD SAID WORKPIECE, SAID GROOVES BEING OPEN ATONE END OF SAID DEPENDENT PIECES, RESPECTIVELY, TO PERMIT THE STENCIL TOBE MOVED IN AN OUT OF POSITON BETWEEN THE DEPENDENT PIECES BY SLIDINGTHE EDGE PORTIONS, RESPECTIVELY, LONGITUDINALLY OF SAID GROOVES, SAIDGROOVES BEING CLOSED AT THE OPPOSITE END OF SAID DEPENDENT PIECES,RESPECTIVELY, TO LIMIT THE MOVEMENT OF SAID EDGE PORTIONS IN SAIDGROOVES AND TO FIX THE POSITION OF THE STENCIL BETWEEN SAID DEPENDENTPIECES, SAID HOLDING DEVICE BEING MOVABLE UPWARDLY RELATIVE TO THE SAIDHEAD UPON SAID STENCIL MEETING THE RESISTANCE OF A SAID WORKPIECE IN THEDOWNWARD MOVEMENT OF SAID HEAD TOWARD THE WORKPIECE.